共查询到19条相似文献,搜索用时 93 毫秒
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2,3-二甲基-5,6-二烷基吡嗪新香料的合成 总被引:1,自引:0,他引:1
2 ,3 二甲基 5 ,6 二烷基吡嗪是一类重要的有机合成中间体和香料 ,在过去几十年已从咖啡、花生、爆米花、炒核桃、炸土豆等食品中广泛检测出它们的存在 ,是构成这类食物香味的微量有效成分之一[1 ] 。这类香料因其香味强、用量少、安全可靠而受到重视 ,现已有十余种烷基吡嗪类香料实现了商业化生产。合成烷基吡嗪的传统方法是用邻二胺和邻二酮缩合氧化制得[2 ] ,但由于受原料来源的限制 ,不利于新型香料品种的开发。缺电子环状共轭体系的自由基烷基化反应是在这类体系中引入烷基的有效方法之一 ,Torssell等[3] 先后用自由基烷基化反… 相似文献
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Yong Sun Li-Ping Gao Zhi-Qiang Guo Ming-Wu Ding 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):2109-2116
2-alkylthio-3-alkyl-5-arylmethylidene-4H-imidazol-4-ones were synthesized by the S-alkylation and N-alkylation of 2-thioxo-5-arylmethylidene-4-imidazolidinones, which were obtained via a tandem aza-Wittig reaction of vinyliminophosphoranes, carbon disulfide, and excess ammonium hydroxide (28% NH3 in water). 相似文献
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Yu. A. Zhdanov G. N. Dorofeenko V. A. Palchkov 《Chemistry of Heterocyclic Compounds》1966,1(6):547-550
A method is given for synthesizing 2-alkyl-6-phenyl-3, 4-cycloheptenopyrylium perchlorates, obtained in 45–55% yields by acylating cycloheptenylacetophenone with anhydrides of aliphatic acids in the presence of 70% perchloric acid. Treatment of the pyrylium salts with ammonia gives a good yield of 2-alkyl-6-phenyl -3, 4-cycloheptenopyridine. 相似文献
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Photosensitized hydrogen abstraction from 2-alkyl-1,3-dioxolanes by triplet benzophenone gives the corresponding 1,3-dioxolan-2-yl radicals and these are trapped by ,β-unsatured ketones yielding monoprotected 1,4-diketones. With open chain ketones (3-buten-2-one and 4-penten-3-one) the yields are low and competitive pathways in part consume the radicals. With cyclic enones however, yields are good as tested with cyclopentenone, cyclohexenone and 4-hydroxy-cyclopentenone. More generally, this is a viable alternative for the synthesis of 1,4-diketones via radicals while the thermal initiation gives only low yield. The reaction cannot be extended to strongly stabilized radicals, such as the 2-phenyl-1,3-dioxolanyl radical. 相似文献
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The reaction of cyclopentylidenecyanothiocetamide with cyanothioacetamide andN-methylmorpholine gaveN-methylmorpholinium 6-amino-3,5-dicyano-1,4-dihydropyridine-4-spirocyclopentane-2-thiolate, which was used in the syntheses
of substituted 2-alkylthiodihydropyridines and pyrazolodihydropyridine.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1849–1851, October. 1997. 相似文献
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The manganese(III) initiated oxidative free radical reaction between 2-amino-1,4-benzoquinones and benzoylacetonitriles is described. This free radical reaction provides a novel method for the synthesis of spirodione 3 and spirolactone 4. With 5,6-dimethyl-2-methylamino-1,4-benzoquinone, spirodione 3 was obtained exclusively. On the contrary, with 5-methyl-2-methylamino-1,4-benzoquinone, spirolactone 4 was produced in high chemo- and regioselectivity. By heating with sodium acetate, spirodione 3 can be converted to 4 effectively. 相似文献